The process is fairly simple but choosing the proper tools and understanding how to use them will save you lots of time.
Getting Set Up
When you need to drill a hole into concrete, there are a few things you need to do before you get started.
Start by renting or purchasing a quality hammer drill. After all, you will find that drilling into concrete is so much easier with a hammer drill than a standard rotary hammer for a larger job. Hammer cordless power drills are designed so that they rapidly hammer to fracture concrete and the drill portion scoops the fractures out of the hole.
While it’s fine to use a typical rotary drill, keep in mind that the process will be much slower and harder – the concrete doesn’t shave into layers like metal or wood. Instead, you should be willing to pay for the rental of a hammer drill instead of using your rotary tool to drill through the concrete.
When you are drilling through concrete, you’ll find that it really is worth it to pay more for a hammer with more power from a brand that is well-established. Other beneficial settings include a comfortable grip, a second handle for your other hand, a depth stop, and a speed setting.
Once you have the hammer power drill, you’ll want to take the time to get to know it. Before you start using it, make sure that you have taken some time to read through the user’s manual so that you understand what the controls/knobs are for. You want to make sure that you are completely comfortable with your tool before you move on.
Make sure that you are following all safety precautions, including wearing eye protection such as safety goggles. This will help you prevent concrete chips from getting into your eyes. You want to also make sure that you are wearing heavy gloves and hearing protection as well. For larger projects that will result in lots of dust, you should wear a respirator.
You’ll want to insert a high-quality masonry drill bit into your hammer drill. These carbide tipped bits are made to withstand the force of drilling and hammering into dense concrete. Of course, you must make sure that the flutes of the bit are as long as the hole that you are going to be drilling.
These will be what directs the dust out of the hole. A rotary hammer requires a special drill bit, known as an SDS, SDS-MAX (for a hole up to 5/8” diameter, or a spline-shank for a hole that is ¾” or more).
If you are drilling through reinforced concrete and you need to drill deeper than the steel rebar, this will be much more difficult. In this case, you’ll need to use a special rebar-cutting drill bit once you hit metal. In order to avoid the drill overheating, you’ll want to slow down and take a short break from time to time.
It’s important to note that some drills do have a depth control bar or depth setting. If you have taken the time to read through your user manual as we have suggested, you’ll know the proper way to use your tool.
If there is no depth control setting on your tool, you can mark the appropriate depth with masking tape or a pencil mark. If you’re not sure how deep you should drill your hole, it’s important to keep the following in mind.
- Since concrete is a dense and hard material, a screw that is embedded just 1” deep is more than enough to hang lightweight objects. A heavy-duty project will require a much longer screw or even a concrete anchor. If this is the case, you’ll find the minimum embedment listed on the packaging
- In order to ensure that there is plenty of room for the dust that is sure to accumulate, you’ll want to add an additional ½” to the embedment. If you plan to remove the dust after you drill the hole, you don’t have to add ½”
- If you are drilling into a thin or hollow concrete surface, you’ll want to check for fastener specs. You will find that some plastic anchors will require a solid backing and are going to end up falling out if you drill through to the other side
Make sure that you are holding the drill properly. You will need to hold it like a gun, with your index finger on the “trigger.” If there is a handle for your other hand on your drill, make sure that you use it. If there’s not a handle to put your other hand on, you will place it at the back of the drill.
Using Your Drill
At this time, you’ll want to mark the spot on the wall. You’ll want to use a soft pencil and mark a small cross or dot on the wall. Once you do this, it’s time to drill your pilot hole. You drill the pilot hole by placing your drill on the mark and drill briefly on low speed or in short bursts, if you have a drill that does not have a speed control.
The pilot hole is a shallow hole, no more than ¼” that will be the guide for your real hole. If your project will require the use of a large drill bit, you’ll probably want to consider using a smaller one for your pilot hole to increase the stability of your drill.
At this time, you will place your drill into your pilot hole, increase the power and, if your drill happens to have one, you can switch on the hammer function at this time. Make sure that you keep the drill perpendicular to the surface and drill using firm pressure to push the drill forward.
However, you want to avoid being too forceful with it. You will slowly increase the speed of the drill and if necessary, the force. However, you want to make sure that you maintain stability and control of the drill at all times. After all, concrete is not homogenous, so the bit could potentially skate if it happens to hit a pebble or an air pocket.
Always make sure that you are applying enough pressure to hold the drill in place, but don’t force it forward as this could potentially break the bit. As you get more practice, you’ll learn the proper amount of pressure to use.
From time to time – about every 10 to 20 seconds – you’ll want to pull the drill out slightly and push it back in again. This will help to pull the dust out of the hole. In addition, you’ll want to pull it out completely every now and then to allow the drill to cool. This is especially critical if you have a rotary drill since they are known to overheat when you are drilling for an extended period of time with them.
Since there are likely to be times that your dill is not going to go as deep as you might need it to or you may hit a hard piece of concrete, you’ll want to keep a masonry nail nearby to use. This will help to break up the concrete. Of course, you’ll want to avoid driving it so deeply that you can’t remove it. Once you remove the masonry nail, you’ll want to place the drill back into the hole and continue.
It’s important to note that if you start to see metal or sparks start shooting out, you’ve hit the rebar. At this point, you’ll want to stop drilling right away and switch out your bit for a rebar-cutting bit until you get past the obstruction.
Finally, blow out the dust once you have finished drilling your hole. Keep in mind that removing the dust will improve the strength of your concrete anchors. Be sure that you wear your goggles as you use compressed air or a squeeze bulb to blow out the dust. You can use your vacuum to clean up the debris.